Stream Network Dynamics of Non‐Perennial Rivers: Insights From Integrated Surface‐Subsurface Hydrological Modeling of Two Virtual Catchments

Abstract

Understanding the spatio‐temporal dynamics of runoff generation in headwater catchments is challenging, due to the intermittent and fragmented nature of surface flows. The active stream network in non‐perennial rivers contracts and expands, with a dynamic behavior that depends on the complex interplay among climate, topography, and geology. In this work, CATchment HYdrology, an integrated surface–subsurface hydrological model (ISSHM), is used to simulate the stream network dynamics of two virtual catchments with the same, spatially homogeneous, subsurface characteristics (hydraulic conductivity, porosity, water retention curves) but different morphology. We run two sets of simulations to reproduce a sequence of steady‐states at different catchment wetness levels and transient conditions and analyze the joint variations of the stream length (L) and discharge at the outlet (Q) with high spatio‐temporal resolutions. The shape of the L(Q) curves differs in the two catchments but does not depend on the climate forcing, as it is mainly controlled by the underlying topography. We then analyzed the suitability of the topographic wetness index and the contributing area to identify the spatial configuration of the maximum stream length in the two catchments. These two morphometric parameters provided a good estimate of the spatial distribution of the maximum flowing network in both the study catchments. Our numerical simulations indicate that ISSHMs have the potential to accurately describe the spatio‐temporal variations of the stream networks and the processes driving such dynamic behavior and that, overall, they can be useful tools to gain insights into the main physical drivers of non‐perennial streams.

Study on River Protection and Improvement Based on a Comprehensive Statistical Model in a Coastal Plain River Network

“…Generally, due to the importance of the water resource and water ecological environment, the coastal plain river networks play a critical role in maintaining the stability and sustainability of the regional environment, economy and society [3][4][5][6][7]. Since the area of the plain river network is usually located downstream of the river basin, with the rapid development of the local society and the continuous improvement of urbanization, the contradiction between river network protection and local development becomes the most prominent factor that impacts both the regional society and the environment [7,8]. In this study, Pinghu City was selected as a typical coastal city, whose river network is located downstream of southeast China, as shown in Figure 1, and has suffered from water environmental problems for years.…”

“…In this study, Pinghu City was selected as a typical coastal city, whose river network is located downstream of southeast China, as shown in Figure 1, and has suffered from water environmental problems for years. Therefore, it is important for Pinghu City to protect the water environment of its river network along with the development of the local economy and society [8][9][10][11][12]. important for Pinghu City to protect the water environment of its river network along with the development of the local economy and society [8][9][10][11][12].…”

“…Therefore, it is important for Pinghu City to protect the water environment of its river network along with the development of the local economy and society [8][9][10][11][12]. important for Pinghu City to protect the water environment of its river network along with the development of the local economy and society [8][9][10][11][12]. As a natural resource composed of river water area, water quantity, water quality and river function, all of these factors are important for the local society.…”

Improving calibration of groundwater flow models using headwater streamflow intermittence

“…Some physicallybased distributed hydrological models fill this gap by including the subsurface in their framework (Daneshmand et al, 2019;Gao et al, 2021;Mimeau et al, 2024;Niedda & Pirastru, 2014;Querner et al, 2016), but they are often limited to stream reaches and hyporheic zones (Frei et al, 2009;Wondzell et al, 2009) or provide only 2D conceptual simulations (Quichimbo et al, 2020). Fully 3D integrated surface-subsurface hydrological models have been developed to better understand the factors triggering streamflow intermittence with HydroGeoSphere (Gutierrez-Jurado et al, 2021;Gutiérrez-Jurado et al, 2019) or CATHY (CATchment HYdrology) (Azarnivand et al, 2020;Weill et al, 2013;Zanetti et al, 2024) models. These approaches are particularly suitable for assessing the influence of subsurface properties on the saturated areas dynamics, but have limitations in terms of model deployment and computational time.…”